Lenovo G510 - LA9641P No Voltage TL_INVT_PWM After 3V Inverter Replacement & Matrix Backlight Issue

Question

Hello, the plate after replacing the 3V inverter (it was damaged) is the lack of matrix backlight. The rest of the voltages in the LCD connector are correct, after TL_INVT_PWM. With the tape connected, the voltage at pin 8 (TL_INVT_PWM) jumps to a fraction of seconds to 1v followed by 0V. No...

sylweksylwina · Answer

Are the transitions from KBC and UT2 to resistors R441 and R431?

nuda · Answer

I can not locate them because there are no markings for the resistors on the disc. I forgot to write that on the KBC leg 25 (EC_INVT_PWM) voltage 3.3V

sylweksylwina · Answer

It's probably lost somewhere along the way. Resistors are somewhere around the LVDS connector.

nuda · Answer

Nowhere are these resistors visible, not even on a different disc as I have on parts. It would be useful for the LA-9641P boardview.

sylweksylwina · Answer

Search between UT2 and LVDS and KBC connector and connector.
Set the multimeter on the diode test, apply one probe to the connector and fly all resistors

If you do not find it will be somewhere damaged path start from the other side, KBC and UT2. Somewhere they must be

Visually, you can not track down the tracks because you can go in the middle of the disc.

nuda · Answer

This is how I made the transition between UT2 and LVDS (though the resistor is missing), not that I can find a resistor between the NCB and the LVDS, no transition to the connector.

Edit. Do not quote the preceding posts in their entirety. RADU23

Stani12 · Answer

I have boardview only I can not open it any program. It has a .brd extension but nothing moves it. Removed from vinafix.
I do not have time to search. Write how to attach it to the post I throw it. It has 11.1Mb.

Edit.
I have already opened the allegro program and I will put a screenshot right away.

nuda · Answer

It would help me a lot and I would look for a program to move it, it's best to add it to the Computer Instr. Service. Or just add an attachment in this topic

Stani12 · Answer

At the beginning p I am asking for info or such a disc shape. I found the R441 resistor. R431 no. I did not watch the diagram so I do not know if it is represented.

nuda · Answer

Yes the disc is the same

Stani12 · Answer

The arrow indicates R441. Added after 37 [minutes]:  You do not answer anything so I do not know if you already have everything or something missing.

nuda · Answer

PR401 is not manned on these discs, I have a second part and I also do not have that reistor. I do not have the KBC EC_INVT_PWM connection to TL_INVT_PWM as it is in the schematic. So it comes out that the UT2 system is responsible for TL_INVT_PWM only that after connecting the matrix the voltage disappears.

Stani12 · Answer

The voltage was measured on both sides of the resistor? Maybe a defective resistor ?. Also check if there is a short to ground in the ribbon (TL_INVT_PWM line).

nuda · Answer

Forgive me that only now is writing back but I gave up on the weekend.
So, there is no resistor PR441. The voltage on the leg 8 LVDS without a plugged matrix is 3.6V, after connecting it jumps to 2.5V for a fraction of a second and then drops to zero. I also checked beforehand whether there is a short circuit on the TL_INVT_PWM line and there is no short circuit, with a 124k ohms connected without 128k ohms. I slowly think that the new UT2 chip is damaged, but I'm not sure.

Stani12 · Answer

There is no resistor but is the path ?. I can reprogram the BIOS and kbc. Maybe a different wire is shorted and the system turns off the backlight.

nuda · Answer

The paths are connected in spite of the lack of a resistor (on both boards in the same way), the bios I uploaded normally from the manufacturer did not improve the problem.
The tape or layout will be replaced by the tape later. Because I'm left with nothing else.

Stani12 · Answer

After all, the tape can be measured for shorts and gaps. Enter the matrix model.

nuda · Answer

I come back after a long break, I could not afford to sit at this record for so much time. So the UT2 replacement (two times) did not work, the matrix tape and other efficient components. I left this record for a while. The client could not wait any longer, so he decided to buy a new disc (old bought for further repair / diagnosis). Subject to be closed.

Lenovo G510 - LA9641P No Voltage TL_INVT_PWM After 3V Inverter Replacement & Matrix Backlight Issue

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